Two resins, two routes
Not all bottles are made the same way. At Shijin, PET and PE follow distinct production flows — knowing which applies to your product explains lead times, tooling and cost.
The PET path: injection then stretch-blow
PET runs a two-stage process: raw resin → injection-moulded preform → stretch-blow into a bottle → silk-screen / label → QC → warehouse → ship. The preform is a thick-walled, test-tube-like shape; heated and stretch-blown, it takes the final bottle form with excellent clarity and wall consistency.
We run 30+ automatic blow-moulding lines and 16 injection-moulding machines across our Shenzhen and Huizhou plants, giving the capacity for roughly 200,000 bottles a day.
The PE path: one-step extrusion-blow
PE and PP follow a shorter route: raw resin → blow moulding (formed in one step) → silk-screen → QC → warehouse → ship. The bottle is formed directly, which suits the softer, chemical-resistant bodies used in cleaning and squeeze applications.
Drying: the step nobody sees
Plastic hates moisture during moulding. We dry PET and PE resin at 170–180°C for 3–4 hours, and colour masterbatch at 100–120°C for 2 hours, before it ever reaches a machine. Skip this and you get haze, bubbles and weak walls.
Vertical integration — own plants, own tooling, own decoration — is what lets us hold quality across every one of these steps instead of hoping a subcontractor did.
Colour, built in
Colour is dosed as masterbatch during moulding, not painted on. The ratio sets the effect: transparent uses pure resin; semi-transparent 1–3.5%; solid ~4%; pearl solid 4–6%; high-gloss solid 6–8%; frosted 0.5–3%; and iridescent a hefty 15–18%.